Identification of nonlinearity in conductivity equation via Dirichlet-to-Neumann map

Hyeonbae Kang and Gen Nakamura

We prove that the linear term and quadratic nonlinear term entering a nonlinear elliptic equation of divergence type can be uniquely identified by the Dirichlet to Neuman map. The unique identifiability is proved using the complex geometrical optics solutions and singular solutions.